Fitness-to-drive after adult civilian traumatic brain injury: protocol for a systematic review and meta-analysis

Traumatic brain injury (TBI) poses significant challenges for assessing fitness-to-drive (FTD) and determining the appropriate timing for return-to-driving (RTD) in civilian adults. This systematic review and meta-analysis protocol is designed to offer a comprehensive assessment of RTD timelines post-TBI, examining the effects of injury severity as well as demographic and clinical factors that influence driving capabilities. In response to gaps identified in previous literature-namely, the absence of recent systematic search strategies and thorough quality assessments-this study employs rigorous methodologies for literature search, data extraction, and evaluation of study quality. Our approach aims to provide reliable estimates and detailed analyses of subgroups within the TBI population. The findings aim to support clinical decision-making, inform RTD readiness, and potentially impact policy and driving assessment protocols. Ultimately, this review seeks to contribute to public safety measures, reduce traffic-related harm, and improve life outcomes for individuals recovering from TBI, thereby filling a vital research niche in neurotrauma rehabilitation.

Functional improvements associated with cranioplasty after stroke and traumatic brain injury: a cohort study

OBJECTIVE

Decompressive craniectomy is part of the acute management of several neurosurgical illnesses, and is commonly followed by cranioplasty. Data are still scarce on the functional and cognitive outcomes following cranioplasty. We aim to evaluate these outcomes in patients who underwent cranioplasty following traumatic brain injury (TBI) or stroke.

METHODS

In this prospective cohort, we assessed 1-month and 6-month neuropsychological and functional outcomes in TBI and stroke patients who underwent cranioplasty at a Brazilian tertiary center. The primary outcome was the change in the Digits Test at 1 and 6 months after cranioplasty. Repeated measures general linear models were employed to assess the patients' evolution and interactions with baseline characteristics. Effect size was estimated by the partial η2.

RESULTS

A total of 20 TBI and 14 stroke patients were included (mean age 42 ± 14 years; 52.9% male; average schooling 9.5 ± 3.8 years; 91.2% right-handed). We found significant improvements in the Digits Tests up to 6 months after cranioplasty (p = 0.004, partial η2 = 0.183), as well as in attention, episodic memory, verbal fluency, working memory, inhibitory control, visuoconstructive and visuospatial abilities (partial η2 0.106-0.305). We found no interaction between the cranioplasty effect and age, sex or schooling. Patients submitted to cranioplasty earlier (<1 year) after injury had better outcomes.

CONCLUSION

Cognitive and functional outcomes improved after cranioplasty following decompressive craniectomy for stroke or TBI. This effect was consistent regardless of age, sex, or education level and persisted after 6 months. Some degree of spontaneous improvement might have contributed to the results.

Brain glucose metabolism and gray matter volume in retired professional soccer players: a cross-sectional [18F]FDG-PET/MRI study

BACKGROUND

 Professional soccer athletes are exposed to repetitive head impacts and are at risk of developing chronic traumatic encephalopathy.

OBJECTIVE

 To evaluate regional brain glucose metabolism (rBGM) and gray matter (GM) volume in retired soccer players (RSPs).

METHODS

 Male RSPs and age and sex-matched controls prospectively enrolled between 2017 and 2019 underwent neurological and neuropsychological evaluations, brain MRI and [18F]FDG-PET in a 3.0-Tesla PET/MRI scanner. Visual analysis was performed by a blinded neuroradiologist and a blinded nuclear physician. Regional brain glucose metabolism and GM volume were assessed using SPM8 software. Groups were compared using appropriate statistical tests available at SPM8 and R.

RESULTS

 Nineteen RSPs (median [IQR]: 62 [50-64.5] years old) and 20 controls (60 [48-73] years old) were included. Retired soccer players performed worse on mini-mental state examination, digit span, clock drawing, phonemic and semantic verbal fluency tests, and had reduced rBGM in the left temporal pole (pFDR = 0.008) and the anterior left middle temporal gyrus (pFDR = 0.043). Semantic verbal fluency correlated with rBGM in the right hippocampus, left temporal pole, and posterior left middle temporal gyrus (p ≤ 0.042). Gray matter volume reduction was observed in similar anatomic regions but was less extensive and did not survive correction for multiple comparisons (pFDR ≥ 0.085). Individual [18F]FDG-PET visual analysis revealed seven RSPs with overt hypometabolism in the medial and lateral temporal lobes, frontal lobes, and temporoparietal regions. Retired soccer players had a higher prevalence of septum pellucidum abnormalities on MRI.

CONCLUSION

 Retired soccer players had reduced rBGM and GM volume in the temporal lobes and septum pellucidum abnormalities, findings possibly related to repetitive head impacts.

Oculomotor, vestibular, reaction time, and cognitive tests as objective measures of neural deficits in patients post COVID-19 infection

Objective

An alarming proportion (>30%) of patients affected by SARS-CoV-2 (COVID-19) continue to experience neurological symptoms, including headache, dizziness, smell and/or taste abnormalities, and impaired consciousness (brain fog), after recovery from the acute infection. These symptoms are self-reported and vary from patient to patient, making it difficult to accurately diagnose and initiate a proper treatment course. Objective measures to identify and quantify neural deficits underlying the symptom profiles are lacking. This study tested the hypothesis that oculomotor, vestibular, reaction time, and cognitive (OVRT-C) testing using eye-tracking can objectively identify and measure functional neural deficits post COVID-19 infection.

Methods

Subjects diagnosed with COVID-19 (n = 77) were tested post-infection with a battery of 20 OVRT-C tests delivered on a portable eye-tracking device (Neurolign Dx100). Data from 14 tests were compared to previously collected normative data from subjects with similar demographics. Post-COVID subjects were also administered the Neurobehavioral Symptom Inventory (NSI) for symptom evaluation.

Results

A significant percentage of post COVID-19 patients (up to 86%) scored outside the norms in 12 out of 14 tests, with smooth pursuit and optokinetic responses being most severely affected. A multivariate model constructed using stepwise logistic regression identified 6 metrics as significant indicators of post-COVID patients. The area under the receiver operating characteristic curve (AUC) was 0.89, the estimated specificity was 98% (with cutoff value of 0.5) and the sensitivity was 88%. There were moderate but significant correlations between NSI domain key variables and OVRT-C tests.

Conclusions

This study demonstrates the feasibility of OVRT-C testing to provide objective measures of neural deficits in people recovering from COVID-19 infection. Such testing may serve as an efficient tool for identifying hidden neurological deficits post COVID-19, screening patients at risk of developing long COVID, and may help guide rehabilitation and treatment strategies.

A novel deep learning approach using AlexNet for the classification of electroencephalograms in Alzheimer's Disease and Mild Cognitive Impairment

Alzheimer's Disease (AD) is the most common form of dementia. Mild Cognitive Impairment (MCI) is the term given to the stage describing prodromal AD and represents a 'risk factor' in early-stage AD diagnosis from normal cognitive decline due to ageing. The electroencephalogram (EEG) has been studied extensively for AD characterization, but reliable early-stage diagnosis continues to present a challenge. The aim of this study was to introduce a novel way of classifying between AD patients, MCI subjects, and age-matched healthy control (HC) subjects using EEG-derived feature images and deep learning techniques. The EEG recordings of 141 age-matched subjects (52 AD, 37 MCI, 52 HC) were converted into 2D greyscale images representing the Pearson correlation coefficients and the distance Lempel-Ziv Complexity (dLZC) between the 21 EEG channels. Each feature type was computed from EEG epochs of 1s, 2s, 5s and 10s segmented from the original recording. The CNN architecture AlexNet was modified and employed for this three-way classification task and a 70/30 split was used for training and validation with each of the different epoch lengths and EEG-derived images. Whilst a maximum classification accuracy of 73.49% was obtained using dLZC-derived images from 10s epochs as input to the model, the classification accuracy reached 98.13% using the images obtained from Pearson correlation coefficients and 5s epochs. Clinical Relevance- The preliminary findings from this study show that deep learning applied to the analysis of the EEG can classify subjects with accuracies close to 100.

Level of knowledge and misconceptions about brain concussion in Brazilian adults

BACKGROUND

Brain concussion (BC) is seen as a public health priority due to its high incidence and morbidity rate, among thousands of people around the world. There are needs for fast identification, accurate diagnosis and correct management in order to reduce the short and long-term problems relating to BC. Proper knowledge of BC in the population and among clinicians is a critical factor in achieving this.

OBJECTIVES

To evaluate the level of self-reported BC knowledge and gaps/misconceptions, and to identify variables correlated with this level.

METHODS

A cross-sectional descriptive survey was performed. A Brain Concussion Knowledge Questionnaire (BCKQ) that had been created to capture data was widely distributed. Total scores, domain partial scores and percentages of correct and incorrect answers were calculated to ascertain the level of knowledge relating to BC.

RESULTS

The sample was formed by 1,247 Brazilian adults (age: 41.7±11.8 years). Partial scores of the BCKQ revealed the existence of poor knowledge and misconceptions in all domains of the questionnaire, especially regarding questions about recovery from and management of BC. Moderate correlations between BCKQ scores and professions (p=0.312; P=0.00) or previous brain concussion knowledge (p=0.489; P=0.00) were observed. In a multiple linear regression model, age, profession and sports practice were predictors of BC knowledge.

CONCLUSION

This first study to analyze the level of BC knowledge in a sample of Brazilian adults suggests that poor knowledge and misconceptions are present. Thus, meaningful and useful information was provided by this study for developing health education programs about BC for the population in order to improve fast diagnosis and correct BC management.

Cannabinoids in Neurology - Position paper from Scientific Departments from Brazilian Academy of Neurology

Cannabinoids comprehend endocannabinoids, phytocannabinoids, and synthetic cannabinoids, with actions both in the central and peripherical nervous systems. A considerable amount of publications have been made in recent years, although cannabis has been known for over a thousand years. Scientific Departments from the Brazilian Academy of Neurology described evidence for medical use in their areas. Literature is constantly changing, and possible new evidence can emerge in the next days or months. Prescription of these substances must be discussed with patients and their families, with knowledge about adverse events and their efficacy.

Deep learning of resting-state electroencephalogram signals for three-class classification of Alzheimer's disease, mild cognitive impairment and healthy ageing

Objective.This study aimed to produce a novel deep learning (DL) model for the classification of subjects with Alzheimer's disease (AD), mild cognitive impairment (MCI) subjects and healthy ageing (HA) subjects using resting-state scalp electroencephalogram (EEG) signals.Approach.The raw EEG data were pre-processed to remove unwanted artefacts and sources of noise. The data were then processed with the continuous wavelet transform, using the Morse mother wavelet, to create time-frequency graphs with a wavelet coefficient scale range of 0-600. The graphs were combined into tiled topographical maps governed by the 10-20 system orientation for scalp electrodes. The application of this processing pipeline was used on a data set of resting-state EEG samples from age-matched groups of 52 AD subjects (82.3 ± 4.7 years of age), 37 MCI subjects (78.4 ± 5.1 years of age) and 52 HA subjects (79.6 ± 6.0 years of age). This resulted in the formation of a data set of 16197 topographical images. This image data set was then split into training, validation and test images and used as input to an AlexNet DL model. This model was comprised of five hidden convolutional layers and optimised for various parameters such as learning rate, learning rate schedule, optimiser, and batch size.Main results.The performance was assessed by a tenfold cross-validation strategy, which produced an average accuracy result of 98.9 ± 0.4% for the three-class classification of AD vs MCI vs HA. The results showed minimal overfitting and bias between classes, further indicating the strength of the model produced.Significance.These results provide significant improvement for this classification task compared to previous studies in this field and suggest that DL could contribute to the diagnosis of AD from EEG recordings.

Individual versus task differences in slow potential generators

Average slow potentials (SPs) can be computed from any voluntary task, minimally involving attention to anticipated stimuli. Their topography when recorded by large electrode arrays even during simple tasks is complex, multifocal, and its generators appear to be equally multifocal and highly variable across subjects. Various sources of noise of course contaminate such averages and must contribute to the topographic complexity. Here, we report a study in which the non-averaged SP band (0 to 1 Hz) was analyzed by independent components (ICA), from 256 channel recordings of 18 subjects, during four task conditions (resting, visual attention, CPT, and Stroop). We intended to verify whether the replicable SP generators (between two separate day sessions) modeled as current density reconstruction on structural MRI sets were individual-specific, and if putative task-related differences were systematic across subjects. Typically, 3 ICA components (out of 10) explained SPs in each task and subject, and their combined generators were highly variable across subjects: although some occipito-temporal and medial temporal areas contained generators in most subjects; the overall patterns were obviously variable, with no single area common to all 18 subjects. Linear regression modeling to compare combined generators (from all ICA components) between tasks and sessions showed significantly higher correlations between the four tasks than between sessions for each task. Moreover, it was clear that no common task-specific areas could be seen across subjects. Those results represent one more instance in which individual case analyses favor the hypothesis of individual-specific patterns of cortical activity, regardless of task conditions. We discuss this hypothesis with respect to results from the beta band, from individual-case fMRI studies, and its corroboration by functional neurosurgery and the neuropsychology of focal lesions.

Use of a Questionnaire to Measure Concussion Knowledge in Brazilian adults

Objective

We aimed to evaluate the self-reported concussion knowledge of the general population, to observe and describe any gaps in the knowledge and misconceptions, and to identify the variables that influence the concussion knowledge.

Background

Concussion represents 80–90% of Traumatic Brain Injury (TBI) causes and its higher incidence is related to sports. The United States Centers for Disease Control estimates a TBI annual incidence ranging from 1.6 to 3.8 million cases, including concussions related to sport. Thus, it is seen as a public health priority. Adequate general population knowledge is a critical issue to correct diagnosis and management of concussion.

Design/Methods

We conducted a cross-sectional descriptive survey. A Concussion knowledge Questionnaire (CKQ) was created to capture data on concussion identification and causes, concussion consequences, recovery and management, and sport-related concussion The number of the sample correct and incorrect answers was calculated to measure the percent of concussion knowledge by CKQ domain.

Results

The sample was formed by 1247 Brazilian adults with a mean age of 41.7 (±11.8) years and high level of schooling. The total score in the CKQ was a mean of 20 (±10) points, which corresponds to a rate of 41.6% of correct answers. Thus, there is poor knowledge in all domains of the CKQ. Only 35.5% of correct answers were registered regarding the main symptoms of a concussion. Similarly, the higher number of incorrect answers was related to questions about recovery and management of a concussion.

Conclusions

Our study is the first to examine the concussion knowledge in a sample of Brazilian adults and provide useful information for development of concussion education programs. Our findings suggest very poor concussion knowledge in sample studied. More larger and meaningful research is needed to investigate the concussion knowledge and the variables that may interfere in the knowledge of the Brazilian general.

Chronic traumatic encephalopathy – a study in Brazilian retired soccer players

Objective

Evaluate the neurological, neuopsychological and electroencephalogram (EEG) findings in a cohort of retired soccer players.

Background

Chronic traumatic encephalopathy (CTE) is considered to be a consequence of exposure to repeated head traumas, but evidence suggests that a single moderate or severe traumatic brain injury can also induce progressive neuropathological changes.

Design/Methods

Prospective observational study that evaluated 26 retired soccer players and 14 controls. The retired athletes and controls were submitted to neurological evaluation, neuropsychological evaluation and EEG.

Results

In general, the soccer players performed well in tests, within the normal range. 15 soccer players had a history of previous TBI/concussion. In the retired group the average age was 60.4 years (55.7 in the CG), average of 11.7 schooling years (13.7 in the CG). The average results in MMSE was 26.6 (29 in the CG), the average digit span in backwards was 3.1 (3.8 in the CG), the average verbal fluency for animals was 15.6 (24 in the CG) and the average clock-drawing test was 8.96 (9 in the CG). Visual EEG analysis showed a predominance of posterior alpha activity between 9.0 and 12.0 Hz (mean 10.3 Hz) in the soccer participants and 11 Hz in the control group (CG). The analysis wiht low resolution electromagnetic tomography (LORETA) showed that 11 soccer players had hippocampal asymmetry (5 had less activity in the right hippocampus and 6 had less activity in the left hippocampus).

Conclusions

Although the performance of the athletes in the tests was within the normal range, the means were always inferior to those of the controls. Almost half of the players presented asymmetry in the analysis by LORETA, although visual EEG analysis was normal. This may indicate that EEG changes may be earlier and more sensitive than clinical changes. These data are preliminary and further analysis are needed.

Traumatic brain injury pharmacological treatment: recommendations

ABSTRACT This article presents the recommendations on the pharmacological treatment employed in traumatic brain injury (TBI) at the outpatient clinic of the Cognitive Rehabilitation after TBI Service of the Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, Brazil. A systematic assessment of the consensus reached in other countries, and of articles on TBI available in the PUBMED and LILACS medical databases, was carried out. We offer recommendations of pharmacological treatments in patients after TBI with different symptoms.

Chronic Traumatic Encephalopathy Presenting as Alzheimer's Disease in a Retired Soccer Player

The relationship between soccer and chronic traumatic encephalopathy (CTE) is not well established. We report clinicopathological correlations in an 83-year-old retired center-back soccer player, with no history of concussion, manifesting typical Alzheimer-type dementia. Examination revealed mixed pathology including widespread CTE, moderate Alzheimer's disease, hippocampal sclerosis, and TDP-43 proteinopathy. This case adds to a few CTE cases described in soccer players. Furthermore, it corroborates that CTE may present clinically as typical Alzheimer-type dementia. Further studies investigating the extent to which soccer is a risk for CTE are needed.

Alpha band EEG coherence in healthy nonagenarians

ABSTRACT Electroencephalographic (EEG) coherence is a parameter that enables evaluation of cerebral connectivity. It may be related to the functional state of the brain. In the elderly, it may reflect the neuronal loss caused by aging. Objective To describe characteristics of coherence in nonagenarians. Methods We evaluated interhemispheric coherence for the alpha band in 42 cognitively normal individuals aged 90 to 101 years. Coherence values in the occipital electrode (O1O2), in the resting state with closed eyes, were calculated by means of spectral analysis using digital EEG EMSA 32 channels, 12 bits and a frequency of 200 Hz. Results The mean coherence value for the alpha band at O1O2 was 0.65 (SD 0.13). No significant differences were found between men and women. Conclusions The findings from this study did not show any decrease in interhemispheric coherence for the alpha band in cognitively normal nonagenarians. This may be useful as a standard value for this age group.

Comparative analysis of the electroencephalogram in patients with Alzheimer's disease, diffuse axonal injury patients and healthy controls using LORETA analysis

Alzheimer's disease (AD) is a dementia that affects a large contingent of the elderly population characterized by the presence of neurofibrillary tangles and senile plaques. Traumatic brain injury (TBI) is a non-degenerative injury caused by an external mechanical force. One of the main causes of TBI is diffuse axonal injury (DAI), promoted by acceleration-deceleration mechanisms.

Objective

To understand the electroencephalographic differences in functional mechanisms between AD and DAI groups.

Methods

The study included 20 subjects with AD, 19 with DAI and 17 healthy adults submitted to high resolution EEG with 128 channels. Cortical sources of EEG rhythms were estimated by exact low-resolution electromagnetic tomography (eLORETA) analysis.

Results

The eLORETA analysis showed that, in comparison to the control (CTL) group, the AD group had increased theta activity in the parietal and frontal lobes and decreased alpha 2 activity in the parietal, frontal, limbic and occipital lobes. In comparison to the CTL group, the DAI group had increased theta activity in the limbic, occipital sublobar and temporal areas.

Conclusion

The results suggest that individuals with AD and DAI have impairment of electrical activity in areas important for memory and learning.

Traumatic brain injury: An EEG point of view

Traumatic brain injury (TBI) is a silent epidemic. Mild traumatic brain injury (mTBI) causes brain injury that results in electrophysiologic abnormalities visible on electroencephalography (EEG) recordings. The purpose of this brief review was to discuss the importance of EEG findings in traumatic brain injury. Relevant articles published during the 1996-2016 period were retrieved from Medline (PubMed). The keywords were in English and included "traumatic brain injury", "EEG" and "quantitative EEG". We found 460 articles, analyzed 52 and selected 13 articles. EEG after TBI shows slowing of the posterior dominant rhythm and increased diffuse theta slowing, which may revert to normal within hours or may clear more slowly over many weeks. There are no clear EEG or quantitative EEG (qEEG) features unique to mild traumatic brain injury. Although the literature indicates the promise of qEEG in reaching a diagnosis and indicating prognosis of mTBI, further study is needed to corroborate and refine these methods.

Neurophysiologic predictors of motor function in stroke

PURPOSE

Understanding the neural mechanisms of stroke recovery is of paramount importance for neurorehabilitation.

METHODS

For this purpose, we analyzed several TMS and EEG variables and their association with motor recovery. Thirty-five subjects with chronic stroke were recruited. The neurophysiological examination included assessments by transcranial magnetic stimulation (TMS), intra- and inter-hemispheric EEG coherence in different frequency bands (e.g. alpha (8-13 Hz)) as determined by quantitative electroencephalography (qEEG). Motor function was measured by Fugl-Meyer (FM). Multiple univariate and multivariate linear regression analyses were performed to identify the predictors for FM.

RESULTS

Multivariate analyses, showed a significant interaction effect of motor threshold (MT) in the lesioned hemisphere and beta coherence in the unlesioned hemisphere. This interaction suggests that higher beta activity in the unlesioned hemisphere strengthens the negative association between MT and FM scores.

CONCLUSIONS

Our results suggest that MT in the lesioned hemisphere is the strongest predictors of motor recovery after stroke. Moreover, cortical activity in the unlesioned hemisphere measured by qEEG provides additional information, specifying the association between MT and FM scores. Therefore, complementary application of EEG and TMS can help constitute a better model of the lesioned and the unlesioned hemispheres that supports the importance of bihemispheric activity in recovery.

Neurophysiologic Correlates of Post-stroke Mood and Emotional Control

OBJECTIVE

Emotional disturbance is a common complication of stroke significantly affecting functional recovery and quality of life. Identifying relevant neurophysiologic markers associated with post-stroke emotional disturbance may lead to a better understanding of this disabling condition, guiding the diagnosis, development of new interventions and the assessments of treatment response.

METHODS

Thirty-five subjects with chronic stroke were enrolled in this study. The emotion sub-domain of Stroke Impact Scale (SIS-Emotion) was used to assess post-stroke mood and emotional control. The relation between SIS-Emotion and neurophysiologic measures was assessed by using covariance mapping and univariate linear regression. Multivariate analyses were conducted to identify and adjust for potential confounders. Neurophysiologic measures included power asymmetry and coherence assessed by electroencephalography (EEG); and motor threshold, intracortical inhibition (ICI) and intracortical facilitation (ICF) measured by transcranial magnetic stimulation (TMS).

RESULTS

Lower scores on SIS-Emotion was associated with (1) frontal EEG power asymmetry in alpha and beta bands, (2) central EEG power asymmetry in alpha and theta bands, and (3) lower inter-hemispheric coherence over frontal and central areas in alpha band. SIS-Emotion also correlated with higher ICF and MT in the unlesioned hemisphere as measured by TMS.

CONCLUSIONS

To our knowledge, this is the first study using EEG and TMS to index neurophysiologic changes associated with post-stroke mood and emotional control. Our results suggest that inter-hemispheric imbalance measured by EEG power and coherence, as well as an increased ICF in the unlesioned hemisphere measured by TMS might be relevant markers associated with post-stroke mood and emotional control which can guide future studies investigating new diagnostic and treatment modalities in stroke rehabilitation.

Evaluation of patients with Alzheimer's disease before and after dental treatment

Oral infections may play a role in Alzheimer's disease (AD). Objective To describe the orofacial pain, dental characteristics and associated factors in patients with Alzheimer's Disease that underwent dental treatment. Method 29 patients with mild AD diagnosed by a neurologist were included. They fulfilled the Mini Mental State Exam and Pfeffer's questionnaire. A dentist performed a complete evaluation: clinical questionnaire; research diagnostic criteria for temporomandibular disorders; McGill pain questionnaire; oral health impact profile; decayed, missing and filled teeth index; and complete periodontal investigation. The protocol was applied before and after the dental treatment. Periodontal treatments (scaling), extractions and topic nystatin were the most frequent. Results There was a reduction in pain frequency (p=0.014), mandibular functional limitations (p=0.011) and periodontal indexes (p<0.05), and an improvement in quality of life (p=0.009) and functional impairment due to cognitive compromise (p<0.001) after the dental treatment. Orofacial complaints and intensity of pain also diminished. Conclusion The dental treatment contributed to reduce co-morbidities associated with AD and should be routinely included in the assessment of these patients.

Oral infections and orofacial pain in Alzheimer's disease: a case-control study

BACKGROUND

Dental infections are frequent and have recently been implicated as a possible risk factor for Alzheimer's disease (AD). Despite a lack of studies investigating orofacial pain in this patient group, dental conditions are known to be a potential cause of pain and to affect quality of life and disease progression.

OBJECTIVES

To evaluate oral status, mandibular function and orofacial pain in patients with mild AD versus healthy subjects matched for age and gender.

METHODS

Twenty-nine patients and 30 control subjects were evaluated. The protocol comprised a clinical questionnaire and dental exam, research diagnostic criteria for temporomandibular disorders, the McGill Pain Questionnaire, the decayed, missing, and filled teeth index, and included a full periodontal evaluation. AD signs and symptoms as well as associated factors were evaluated by a trained neurologist.

RESULTS

A higher prevalence of orofacial pain (20.7%, p < 0.001), articular abnormalities in temporomandibular joints (p < 0.05), and periodontal infections (p = 0.002) was observed in the study group compared to the control group.

CONCLUSION

Orofacial pain and periodontal infections were more frequent in patients with mild AD than in healthy subjects. Orofacial pain screening and dental and oral exams should be routinely performed in AD patients in order to identify pathological conditions that need treatment thus improving quality of life compromised due to dementia.

Clinician's road map to wavelet EEG as an Alzheimer's disease biomarker

Alzheimer's disease (AD) is considered the main cause of dementia in Western countries. Consequently, there is a need for an accurate, universal, specific and cost-effective biomarker for early AD diagnosis, to follow disease progression and therapy response. This article describes a new diagnostic approach to quantitative electroencephalogram (QEEG) diagnosis of mild and moderate AD. The data set used in this study was composed of EEG signals recorded from 2 groups: (S1) 74 normal subjects, 33 females and 41 males (mean age 67 years, standard deviation = 8) and (S2) 88 probable AD patients (NINCDS-ADRDA criteria), 55 females and 33 males (mean age 74.7 years, standard deviation = 7.8) with mild to moderate symptoms (DSM-IV-TR). Attention is given to sample size and the use of state of the art open source tools (LetsWave and WEKA) to process the EEG data. This innovative technique consists in associating Morlet wavelet filter with a support vector machine technique. A total of 111 EEG features (attributes) were obtained for 162 probands. The results were accuracy of 92.72% and area under the curve of 0.92 (percentage split test). Most important, comparing a single patient versus the total data set resulted in accuracy of 84.56% (leave-one-patient-out test). Particular emphasis was on clinical diagnosis and feasibility of implementation of this low-cost procedure, because programming knowledge is not required. Consequently, this new method can be useful to support AD diagnosis in resource-limited settings.

The effects of automated artifact removal algorithms on electroencephalography-based Alzheimer's disease diagnosis

Over the last decade, electroencephalography (EEG) has emerged as a reliable tool for the diagnosis of cortical disorders such as Alzheimer's disease (AD). EEG signals, however, are susceptible to several artifacts, such as ocular, muscular, movement, and environmental. To overcome this limitation, existing diagnostic systems commonly depend on experienced clinicians to manually select artifact-free epochs from the collected multi-channel EEG data. Manual selection, however, is a tedious and time-consuming process, rendering the diagnostic system “semi-automated.” Notwithstanding, a number of EEG artifact removal algorithms have been proposed in the literature. The (dis)advantages of using such algorithms in automated AD diagnostic systems, however, have not been documented; this paper aims to fill this gap. Here, we investigate the effects of three state-of-the-art automated artifact removal (AAR) algorithms (both alone and in combination with each other) on AD diagnostic systems based on four different classes of EEG features, namely, spectral, amplitude modulation rate of change, coherence, and phase. The three AAR algorithms tested are statistical artifact rejection (SAR), blind source separation based on second order blind identification and canonical correlation analysis (BSS-SOBI-CCA), and wavelet enhanced independent component analysis (wICA). Experimental results based on 20-channel resting-awake EEG data collected from 59 participants (20 patients with mild AD, 15 with moderate-to-severe AD, and 24 age-matched healthy controls) showed the wICA algorithm alone outperforming other enhancement algorithm combinations across three tasks: diagnosis (control vs. mild vs. moderate), early detection (control vs. mild), and disease progression (mild vs. moderate), thus opening the doors for fully-automated systems that can assist clinicians with early detection of AD, as well as disease severity progression assessment.

Sport-related concussions

Traumatic brain injury (TBI) is a major cause of lifelong disability and death worldwide. Sport-related traumatic brain injury is an important public health concern. The purpose of this review was to highlight the importance of sport-related concussions. Concussion refers to a transient alteration in consciousness induced by external biomechanical forces transmitted directly or indirectly to the brain. It is a common, although most likely underreported, condition. Contact sports such as American football, rugby, soccer, boxing, basketball and hockey are associated with a relatively high prevalence of concussion. Various factors may be associated with a greater risk of sport-related concussion, such as age, sex, sport played, level of sport played and equipment used. Physical complaints (headache, fatigue, dizziness), behavioral changes (depression, anxiety, irritability) and cognitive impairment are very common after a concussion. The risk of premature return to activities includes the prolongation of post-concussive symptoms and increased risk of concussion recurrence.

A successful case of anti-NMDAR encephalitis without tumor treated with a prolonged regimen of plasmapheresis

Anti-NMDA receptor encephalitis is a severe but treatable autoimmune disease of the CNS. However, the use of immunotherapy and long-term outcomes have yet to be defined for this disease. We describe a case of an 18-year-old male diagnosed with anti-NMDAR encephalitis not associated with tumor, which did not respond to initial treatment with immunoglobulin, followed by corticosteroids, cyclophosphamide and evolved with significant clinical improvement after a prolonged course of plasmapheresis. Although it is not possible to affirm the good outcome was due solely to the prolonged plasmapheresis regimen, recently published data shows that improvement may take weeks or months to occur. This case discloses another therapeutic possibility for patients with refractory disease who fail to respond to recommended first-line and second-line therapy.

Comprehensive cognitive and cerebral hemodynamic evaluation after cranioplasty

Decompressive craniectomy is an established procedure to lower intracranial pressure and can save patients' lives. However, this procedure is associated with delayed cognitive decline and cerebral hemodynamics complications. Studies show the benefits of cranioplasty beyond cosmetic aspects, including brain protection, and functional and cerebrovascular aspects, but a detailed description of the concrete changes following this procedure are lacking. In this paper, the authors report a patient with trephine syndrome who underwent cranioplasty; comprehensive cognitive and cerebral hemodynamic evaluations were performed prior to and following the cranioplasty. The discussion was based on a critical literature review.

Changes in Cortical Activity During Real and Imagined Movements: an ERP Study

This study aims to compare the topographic distribution of cortical activation between real and imagined movement through event-related potential (ERP). We are specifically interested in identifying, the topographic distribution of activated areas, the intensity of activated areas, and the temporal occurrence of these activations on preparation and motor response phases. Twelve healthy and right handed subjects were instructed to perform a task under real and imagery conditions. The task was performed simultaneously to electroencephalographic (EEG) recording. When compared the conditions, we found a statistically significant difference in favor of real condition revealed by performing an unpaired t-test with multiple corrections of Bonferroni, demonstrating negative activity on electrode C3 and positive activity on the electrode C4 only in motor response phase. These findings revealed similar functional connections established during real and imagery conditions, suggesting that there are common neural substrate and similar properties of functional integration shared by conditions.

Index of alpha/theta ratio of the electroencephalogram: a new marker for Alzheimer's disease

Objective: We evaluated quantitative EEG measures to determine a screening index to discriminate Alzheimer’s disease (AD) patients from normal individuals.

Methods: Two groups of individuals older than 50 years, comprising a control group of 57 normal volunteers and a study group of 50 patients with probable AD, were compared. EEG recordings were obtained from subjects in a wake state with eyes closed at rest for 30 min. Logistic regression analysis was conducted.

Results: Spectral potentials of the alpha and theta bands were computed for all electrodes and the alpha/theta ratio calculated. Logistic regression of alpha/theta of the mean potential of the C3 and O1 electrodes was carried out. A formula was calculated to aid the diagnosis of AD yielding 76.4% sensitivity and 84.6% specificity for AD with an area under the ROC curve of 0.92.

Conclusion: Logistic regression of alpha/theta of the spectrum of the mean potential of EEG represents a good marker discriminating AD patients from normal controls.

Characterizing Alzheimer's disease severity via resting-awake EEG amplitude modulation analysis

Changes in electroencephalography (EEG) amplitude modulations have recently been linked with early-stage Alzheimer's disease (AD). Existing tools available to perform such analysis (e.g., detrended fluctuation analysis), however, provide limited gains in discriminability power over traditional spectral based EEG analysis. In this paper, we explore the use of an innovative EEG amplitude modulation analysis technique based on spectro-temporal signal processing. More specifically, full-band EEG signals are first decomposed into the five well-known frequency bands and the envelopes are then extracted via a Hilbert transform. Each of the five envelopes are further decomposed into four so-called modulation bands, which were chosen to coincide with the delta, theta, alpha and beta frequency bands. Experiments on a resting-awake EEG dataset collected from 76 participants (27 healthy controls, 27 diagnosed with mild-AD, and 22 with moderate-AD) showed significant differences in amplitude modulations between the three groups. Most notably, i) delta modulation of the beta frequency band disappeared with an increase in disease severity (from mild to moderate AD), ii) delta modulation of the theta band appeared with an increase in severity, and iii) delta modulation of the beta frequency band showed to be a reliable discriminant feature between healthy controls and mild-AD patients. Taken together, it is hoped that the developed tool can be used to assist clinicians not only with early detection of Alzheimer's disease, but also to monitor its progression.

BPSD following traumatic brain injury

Annually, 700,000 people are hospitalized with brain injury acquired after traumatic brain injury (TBI) in Brazil.

OBJECTIVE

We aim to review the basic concepts related to TBI, and the most common Behavioral and Psychological Symptoms of Dementia (BPSD) findings in moderate and severe TBI survivors. We also discussed our strategies used to manage such patients in the post-acute period.

METHODS

Fifteen TBI outpatients followed at the Center for Cognitive Rehabilitation Post-TBI of the Clinicas Hospital of the University of São Paulo were submitted to a neurological, neuropsychological, speech and occupational therapy evaluation, including the Mini-Mental State Examination. Rehabilitation strategies will then be developed, together with the interdisciplinary team, for each patient individually. Where necessary, the pharmacological approach will be adopted.

RESULTS

Our study will discuss options of pharmacologic treatment choices for cognitive, behavioral, or affective disorders following TBI, providing relevant information related to a structured cognitive rehabilitation service and certainly will offer an alternative for patients and families afflicted by TBI.

CONCLUSION

Traumatic brain injury can cause a variety of potentially disabling psychiatric symptoms and syndromes. Combined behavioral and pharmacological strategies, in the treatment of a set of highly challenging behavioral problems, appears to be essential for good patient recovery.

Lack of systematic topographic difference between attention and reasoning beta correlates

Based on previous evidence for individual-specific sets of cortical areas active during simple attention tasks, in this work we intended to perform within individual comparisons of task-induced beta oscillations between visual attention and a reasoning task. Since beta induced oscillations are not time-locked to task events and were first observed by Fourier transforms, in order to analyze the cortical topography of attention induced beta activity, we have previously computed corrected-latency averages based on spontaneous peaks of band-pass filtered epochs. We then used Independent Component Analysis (ICA) only to single out the significant portion of averaged data, above noise levels. In the present work ICA served as the main, exhaustive means for decomposing beta activity in both tasks, using 128-channel EEG data from 24 subjects. Given the previous observed similarity between tasks by visual inspection and by simple descriptive statistics, we now intended another approach: to quantify how much each ICA component obtained in one task could be explained by a linear combination of the topographic patterns from the other task in each individual. Our hypothesis was that the major psychological difference between tasks would not be reflected as important topographic differences within individuals. Results confirmed the high topographic similarity between attention and reasoning beta correlates in that few components in each individual were not satisfactorily explained by the complementary task, and if those could be considered "task-specific", their scalp distribution and estimated cortical sources were not common across subjects. These findings, along with those from fMRI studies preserving individual data and conventional neuropsychological and neurosurgical observations, are discussed in support of a new functional localization hypothesis: individuals use largely different sets of cortical association areas to perform a given task, but those individual sets do not change importantly across tasks that differ in major psychological processes.

Alzheimer's disease qEEG: spectral analysis versus coherence. Which is the best measurement?

There is evidence in electroencephalography that alpha, theta and delta band oscillations reflect cognitive and memory performances and that quantitative techniques can improve the electroencephalogram (EEG) sensitivity. This paper presents the results of comparative analysis of qEEG variables as reliable markers for Alzheimer's disease (AD). We compared the sensitivity and specificity between spectral analysis (spectA) and coherence (Coh) within the same group of AD patients. SpectA and Coh were calculated from EEGs of 40 patients with mild to moderate AD and 40 healthy elderly controls. The peak of spectA was smaller in the AD group than in controls. AD group showed predominance of slow spectA in theta and delta bands and a significant reduction of inter-hemispheric Coh for occipital alpha 2 and beta 1 and for frontal delta sub-band. ROC curve supported that alpha band spectA was more sensitive than coherence to differentiate controls from AD.

Cognitive mechanisms and motor control during a saccadic eye movement task: evidence from quantitative electroencephalography

The saccadic movement is an important behavioral measure used to investigate several cognitive processes, including attention and sensorimotor integration. The present study aimed at investigating changes in beta coherence over frontal, motor, occipital, and parietal cortices during the performance of two different conditions of a prosacadic paradigm. The conditions involved a different pattern of stimulus presentation: a fixed and random stimulus presentation. Twelve healthy volunteers (three male, mean age of 26.25 (SD=4.13) performed the task, while their brain activity pattern was recorded using quantitative electroencephalography. The results showed an interaction between factors condition and moment for the pair of electrode C3/C4. We observed a main effect for moment to CZ/C4, FZ/F3, and P3/PZ. We also found a main effect for condition to FZ/F4, P3/P4, and O1/O2. Our results demonstrated an important role of the inter-connection of the two hemispheres in visual search and movement preparation. The study demonstrates an automation of action and reduction of the focus of attention during the task. We also found that the inter-hemispheric beta coherence plays an important role in the differentiation of the two conditions, and that beta in the right frontal cortex is able to differentiate the conditions, demonstrating a greater involvement of procedural memory in fixed condition. Our results suggest a neuronal specialization in the execution of prosacadic paradigm involving motor task sequence.

Sensorimotor integration and psychopathology: motor control abnormalities related to psychiatric disorders

OBJECTIVES

Recent evidence is reviewed to examine relationships among sensorimotor and cognitive aspects in some important psychiatry disorders. This study reviews the theoretical models in the context of sensorimotor integration and the abnormalities reported in the most common psychiatric disorders, such as Alzheimer's disease, autism spectrum disorder and squizophrenia.

METHODS

The bibliographical search used Pubmed/Medline, ISI Web of Knowledge, Cochrane data base and Scielo databases. The terms chosen for the search were: Alzheimer's disease, AD, autism spectrum disorder, and Squizophrenia in combination with sensorimotor integration. Fifty articles published in English and were selected conducted from 1989 up to 2010.

RESULTS

We found that the sensorimotor integration process plays a relevant role in elementary mechanisms involved in occurrence of abnormalities in most common psychiatric disorders, participating in the acquisition of abilities that have as critical factor the coupling of different sensory data which will constitute the basis of elaboration of consciously goal-directed motor outputs. Whether these disorders are associated with an abnormal peripheral sensory input or defective central processing is still unclear, but some studies support a central mechanism.

CONCLUSION

Sensorimotor integration seems to play a significant role in the disturbances of motor control, like deficits in the feedforward mechanism, typically seen in AD, autistic and squizophrenic patients.

Diagnosis of Alzheimer's disease in Brazil: Supplementary exams

This article presents a review of the recommendations on supplementary exams employed for the clinical diagnosis of Alzheimer’s disease (AD) in Brazil published in 2005. A systematic assessment of the consensus reached in other countries, and of articles on AD diagnosis in Brazil available on the PUBMED and LILACS medical databases, was carried out. Recommended laboratory exams included complete blood count, serum creatinine, thyroid stimulating hormone (TSH), albumin, hepatic enzymes, Vitamin B12, folic acid, calcium, serological reactions for syphilis and serology for HIV in patients aged younger than 60 years with atypical clinical signs or suggestive symptoms. Structural neuroimaging, computed tomography or – preferably – magnetic resonance exams, are indicated for diagnostic investigation of dementia syndrome to rule out secondary etiologies. Functional neuroimaging exams (SPECT and PET), when available, increase diagnostic reliability and assist in the differential diagnosis of other types of dementia. The cerebrospinal fluid exam is indicated in cases of pre-senile onset dementia with atypical clinical presentation or course, for communicant hydrocephaly, and suspected inflammatory, infectious or prion disease of the central nervous system. Routine electroencephalograms aid the differential diagnosis of dementia syndrome with other conditions which impair cognitive functioning. Genotyping of apolipoprotein E or other susceptibility polymorphisms is not recommended for diagnostic purposes or for assessing the risk of developing the disease. Biomarkers related to the molecular alterations in AD are largely limited to use exclusively in research protocols, but when available can contribute to improving the accuracy of diagnosis of the disease.

Improving Alzheimer's disease diagnosis with machine learning techniques

There is not a specific test to diagnose Alzheimer's disease (AD). Its diagnosis should be based upon clinical history, neuropsychological and laboratory tests, neuroimaging and electroencephalography (EEG). Therefore, new approaches are necessary to enable earlier and more accurate diagnosis and to follow treatment results. In this study we used a Machine Learning (ML) technique, named Support Vector Machine (SVM), to search patterns in EEG epochs to differentiate AD patients from controls. As a result, we developed a quantitative EEG (qEEG) processing method for automatic differentiation of patients with AD from normal individuals, as a complement to the diagnosis of probable dementia. We studied EEGs from 19 normal subjects (14 females/5 males, mean age 71.6 years) and 16 probable mild to moderate symptoms AD patients (14 females/2 males, mean age 73.4 years. The results obtained from analysis of EEG epochs were accuracy 79.9% and sensitivity 83.2%. The analysis considering the diagnosis of each individual patient reached 87.0% accuracy and 91.7% sensitivity.

Effects of functional electro-stimulation in the theta-band coherence: a quantitative electroencephalograph study

INTRODUCTION

Functional electrical stimulation (FES) is a technique used for rehabilitation of motor and sensory dysfunction and consisted in the application of neuromuscular electrical stimulation concurrently with a functional activity. Previous studies suggest that sensory motor processing during FES stimulation of hand is similar to that of voluntary hand movement.

AIM

To examine the changes in theta band (4-8 Hz) coherence in the centro-parietal and temporo-parietal junction during a FES task. Our hypothesis is that different conditions of electro-stimulation can produce changes in the theta band coherence in the sensory-motor and multisensory integration.

SUBJECTS AND METHODS

The sample was composed of 24 students, male (n =14) and female (n =10), between 25 and 40 years old. Subjects were randomly distributed in three groups: control group (n = 8), G24 (n = 8) and G36 (n = 8). The control group simulated four blocks without electrostimulation been applied. The G24 group was exposed to four blocks of electrostimulation. The G36 group was exposed to six blocks of electrostimulation. We employed FES equipment to stimulate the extension of the right index finger and the electroencephalographic signal was simultaneously recorded.

RESULTS

A main effect was found for the condition, block and electrode in the centro-parietal junction, although we only found a main effect for condition and electrode in the temporo-parietal junction. CONCLUSION. Our results suggest that the functional coupling between the central and parietal areas is directly connected to the priming memory function, although the coupling between temporal and parietal areas is related to the working memory.

EEG-based brain-computer interfaces: an overview of basic concepts and clinical applications in neurorehabilitation

Some patients are no longer able to communicate effectively or even interact with the outside world in ways that most of us take for granted. In the most severe cases, tetraplegic or post-stroke patients are literally 'locked in' their bodies, unable to exert any motor control after, for example, a spinal cord injury or a brainstem stroke, requiring alternative methods of communication and control. But we suggest that, in the near future, their brains may offer them a way out. Non-invasive electroencephalogram (EEG)-based brain-computer interfaces (BCI) can be characterized by the technique used to measure brain activity and by the way that different brain signals are translated into commands that control an effector (e.g., controlling a computer cursor for word processing and accessing the internet). This review focuses on the basic concepts of EEG-based BCI, the main advances in communication, motor control restoration and the downregulation of cortical activity, and the mirror neuron system (MNS) in the context of BCI. The latter appears to be relevant for clinical applications in the coming years, particularly for severely limited patients. Hypothetically, MNS could provide a robust way to map neural activity to behavior, representing the high-level information about goals and intentions of these patients. Non-invasive EEG-based BCIs allow brain-derived communication in patients with amyotrophic lateral sclerosis and motor control restoration in patients after spinal cord injury and stroke. Epilepsy and attention deficit and hyperactive disorder patients were able to downregulate their cortical activity. Given the rapid progression of EEG-based BCI research over the last few years and the swift ascent of computer processing speeds and signal analysis techniques, we suggest that emerging ideas (e.g., MNS in the context of BCI) related to clinical neurorehabilitation of severely limited patients will generate viable clinical applications in the near future.

Does EEG montage influence Alzheimer's disease electroclinic diagnosis?

There is not a specific Alzheimer's disease (AD) diagnostic test. AD diagnosis relies on clinical history, neuropsychological, and laboratory tests, neuroimaging and electroencephalography. Therefore, new approaches are necessary to enable earlier and more accurate diagnosis and to measure treatment results. Quantitative EEG (qEEG) can be used as a diagnostic tool in selected cases. The aim of this study was to answer if distinct electrode montages have different sensitivity when differentiating controls from AD patients. We analyzed EEG spectral peaks (delta, theta, alpha, beta, and gamma bands), and we compared references (Biauricular, Longitudinal bipolar, Crossed bipolar, Counterpart bipolar, and Cz reference). Support Vector Machines and Logistic Regression classifiers showed Counterpart bipolar montage as the most sensitive electrode combination. Our results suggest that Counterpart bipolar montage is the best choice to study EEG spectral peaks of controls versus AD.

EEG spectro-temporal modulation energy: a new feature for automated diagnosis of Alzheimer's disease

There is recent indication that Alzheimer's disease (AD) can be characterized by atypical modulation of electrophysiological brain activity caused by fibrillar amyloid deposition in specific regions of the brain, such as those related to cognition and memory. In this paper, we propose to objectively characterize EEG sub-band modulation in an attempt to develop an automated noninvasive AD diagnostics tool. First, multi-channel full-band EEG signals are decomposed into five well-known frequency sub-bands: delta, theta, alpha, beta, and gamma. The temporal amplitude envelope of each sub-band is then computed via a Hilbert transformation. The proposed 'spectro-temporal modulation energy' feature measures the rate with which each sub-band is modulated. Modulation energy features are computed for 19 referential EEG signals and seven bipolar signals. Salient features are then selected and used to train four different classifiers, namely, support vector machines, logistic regression, classification and regression trees, and neural networks. Experiments with a database of 34 participants, 22 of which have been clinically diagnosed with probable-AD, show a neural network classifier achieving over 91% accuracy, thus significantly outperforming a classifier trained with conventional spectral-based features.

Cognitive rehabilitation following traumatic brain injury

Annually, some 500,000 people are hospitalized with brain lesions acquired after traumatic brain injury (TBI) in Brazil. Between 75,000 and 100,000 individuals die within hours of the event and 70,000 to 90,000 evolve to irreversible loss of some neurological function. The principal causes of TBI include motor vehicle accidents (50%), falls (21%), assaults and robberies (12%) and accidents during leisure activities (10%). Within this context, cognitive rehabilitation, a clinical area encompassing interdisciplinary action aimed at recovery as well as compensation of cognitive functions altered as a result of cerebral injury, is extremely important for these individuals. Therefore, the aim of this study was to review the basic concepts related to TBI, including mechanisms of injury, severity levels of TBI, the most common findings in moderate and severe TBI survivors, and the most frequent cognitive impairments following TBI, and also to discuss the strategies used to handle patients post-TBI. The study results yielded relevant information on a structured cognitive rehabilitation service, representing an alternative for patients and families afflicted by TBI, enabling the generation of multiple research protocols.

Gamma band oscillations in parietooccipital areas during performance of a sensorimotor integration task: a qEEG coherence study

This study aimed to elucidate cortical mechanisms involved in anticipatory actions when 23 healthy right-handed subjects had to catch a free falling object through quantitative electroencephalogram (qEEG). For this reason, we used coherence that represents a measurement of linear covariation between two signals in the frequency domain. In addition, we investigated gamma-band (30-100 Hz) activity that is related to cognitive and somatosensory processes. We hypothesized that gamma coherence will be increase in both parietal and occipital areas during moment after ball drop, due to their involvement in manipulation of objects, visuospatial processing, visual perception, stimuli identification and attention processes. We confirmed our hypothesis, an increase in gamma coherence on P3-P4 (t= -2.15; p=0.033) and PZ-OZ (t= -2.16; p=0.034) electrode pairs was verified for a paired t-test. We conclude that to execute tasks involving anticipatory movements (feedforward mechanisms), like our own task, probably, there is no need of a strong participation of visual areas in the process of information organization to manipulate objects and to process visuospatial information regarding the contact hand-object.

Minor and unsystematic cortical topographic changes of attention correlates between modalities

In this study we analyzed the topography of induced cortical oscillations in 20 healthy individuals performing simple attention tasks. We were interested in qualitatively replicating our recent findings on the localization of attention-induced beta bands during a visual task [1], and verifying whether significant topographic changes would follow the change of attention to the auditory modality. We computed corrected latency averaging of each induced frequency bands, and modeled their generators by current density reconstruction with Lp-norm minimization. We quantified topographic similarity between conditions by an analysis of correlations, whereas the inter-modality significant differences in attention correlates were illustrated in each individual case. We replicated the qualitative result of highly idiosyncratic topography of attention-related activity to individuals, manifested both in the beta bands, and previously studied slow potential distributions [2]. Visual inspection of both scalp potentials and distribution of cortical currents showed minor changes in attention-related bands with respect to modality, as compared to the theta and delta bands, known to be major contributors to the sensory-related potentials. Quantitative results agreed with visual inspection, supporting to the conclusion that attention-related activity does not change much between modalities, and whatever individual changes do occur, they are not systematic in cortical localization across subjects. We discuss our results, combined with results from other studies that present individual data, with respect to the function of cortical association areas.